Hepatitis C(HCV) is a cause of viral infections. There is as yet no adequate treatment for HCV infection but it is believed that inhibition of its RNA polymerase in mammals, particularly humans, would be of benefit.
Published International patent application WO 2005/080399 (Japan Tobacco Inc.) discloses the following fused heterotetracyclic compounds:
where A, X, Cy, G1, G2, G3, G4, G5, G6, R1, R2, R3, R4, R5, R6 and a are defined therein, and their use as HCV polymerase inhibitors.
Published International patent application WO 2006/020082 (Bristol-Myers Squibb Company) discloses the following fused tetracyclic compounds:
where A, B, R1, R2, R3 and n are defined therein, and their use in treating hepatitis C.